Not really, I'm sure the cognoscenti of suits can give the exact Rules, but I think the best advise is to cover your ass--longer than that may get you into bad proportions. Go to the best mens store in town and ask them, then go to the next best mens store, etc, etc.

Someone posted a graphic showing the proper length for the jacket. I don't have a link to that post.

However, the general rule is to have it finished to end so that it does cover your behind, plus about an inch. Then, depending upon your proportions, adjust it as much as a 3/4 inch. So that someone with proportionatly long legs would add half inch to the length. Shorter folks with shorter legs would try to get a shorter coat, giving them longer appearing legs.